---
description: "Reference for Nitric's v0 Python library - Create a signed URL for write access to a file."
---

# Python - bucket.file.upload_url()

Create a signed url for write access to a file.

```python
from nitric.resources import bucket
from nitric.application import Nitric

assets = bucket('assets').allow('writing')

logo = assets.file('images/logo.png')

upload_url = await logo.upload_url()

Nitric.run()
```

## Parameters

<Properties>
  <Property name="expiry" type="number">
    Seconds until link expiry. Maximum of 604800 (7 days).
  </Property>
</Properties>

## Examples

### Create a temporary file upload link for a user

```python
from nitric.resources import bucket
from nitric.application import Nitric

uploads = bucket('uploads').allow('writing')

photo = assets.file('images/photo.png')

photo_url = await logo.upload_url()

Nitric.run()
```
